The head louse, Pediculus humanus capitis, is an obligate ectoparasite that must live on a human host to survive. While the scalp is the primary site of infestation, people often worry about contamination on surfaces like pillows. Finding a live adult louse on a pillow is uncommon because these insects depend on the constant warmth and frequent blood meals provided by the human body. However, debris and remnants from an infestation can be found on bedding.
Understanding Lice Behavior and Survival Off the Scalp
The biological needs of the head louse severely limit its ability to survive away from its host. Lice rely on the stable temperature of the human scalp and must feed on blood several times a day. Once separated from the host, the adult louse begins to weaken rapidly. Adult head lice die within 24 to 48 hours when separated from a host, making the pillow a poor environment for long-term survival.
Nits, or louse eggs, are cemented firmly to hair shafts and are rarely found loose on fabric. They require the host’s body temperature to hatch successfully.
Key Visual Indicators Found on Pillows
When inspecting a pillow used by an infested person, it is unlikely to spot a live, actively crawling louse. A live adult louse is about the size of a sesame seed and ranges in color from grayish-white to tan. Instead, you are more likely to find small, dark specks that are not moving.
These specks may be lice frass, which is the feces left behind by the insect. Frass appears as tiny, dark, pepper-like grains that might be mistaken for dirt or lint. You might also find shed exoskeletons, which are the casings left after a young louse, or nymph, molts as it grows.
Detached hair strands with nits attached are another visual clue on a pillowcase. A nit is a tiny, oval-shaped egg, often whitish or yellowish, glued tightly to a hair shaft. Unlike dandruff or lint, nits are difficult to slide off the hair.
Immediate Actions and Bedding Treatment
Once an infestation is confirmed, cleaning the bedding is a practical step to reduce the risk of re-infestation. The most effective method for treating pillows and linens involves using heat. Machine washing all bedding, including pillowcases and sheets, in hot water is recommended.
The water temperature should be at least 130°F (54°C) for 10 minutes to reliably kill both lice and nits. Following the wash, all items should be placed in a clothes dryer on a high-heat cycle for a minimum of 20 minutes. Non-washable items, such as stuffed animals or decorative pillows, can be sealed in a plastic bag for about 10 days. Alternatively, thoroughly vacuuming mattresses and upholstered furniture removes any loose hairs or debris that may have fallen from the scalp.